For the curious, this is the "complex mathematical question":
In a kind of geek jeopardy, the billboard read:"{first 10-digit prime found in consecutive digits e}.com." The answer, 7427466391.com, would lead a puzzle-sleuth to a Web page with yet another equation to solve, with still no sign the game was hosted by Google.

Mastering that equation would lead someone to a page on Google Labs, the company's research and development department, which reads: "One thing we learned while building Google is that it's easier to find what you're looking for if it comes looking for you. What we're looking for are the best engineers in the world. And here you are.